Route 74 serves the centers of South Windsor, Rockville, Tolland and Willington, much of it following the old 19th-century Tolland Turnpike. The segment from I-84 to US 44 is an important connector to eastern Connecticut.
In late 1931, planning maps showed this route as Route 192.
In 1943, a two-lane section of the Wilbur Cross Highway opened between Willington and Union, including an interchange at Route 32. Route 15 was relocated to the new section, and followed a 5.6 mile overlap with Route 74 through Tolland to get there. The older Route 15, which had continued straight north to Route 20 (now Route 190) in Stafford, became Route 30.
In 1948, the Wilbur Cross Highway was extended southwest to the Charter Oak Bridge in East Hartford, though much of it was two lanes. Route 15 was moved to the new highway, and US 44 was rerouted to overlap with it to Route 74 at Tolland. To the east, US 44 replaced Route 74 to Ashford. (Former US 44 through Bolton and Coventry became US 44A.) The new length of Route 74, from Route 83 to Route 15, was 8.86 miles.
On Sept. 1, 1962, Route 74 was extended westward, overlapping Route 83 and continuing to the Buckland "Five Corners" in South Windsor. Part of this route had recently been added to the state system as SR 802. Curves and drainage had been a problem on this road connecting South Windsor and Ellington, and town officials hoped state improvements were on the way.
Over the next few decades, the Wilbur Cross Highway was widened twice, and by 1980 carried three route numbers from East Hartford to Tolland: Route 15, US 44, and Interstate 86. In 1980, the state simplified things by removing Route 15 from the highway. On Dec. 1, 1982, the state continued by removing the US 44 overlap. US 44 reverted to its pre-1948 alignment, and so did Route 74, extending once again to Ashford. (Signs were changed a month or two later.) This is a rare instance of a Connecticut state highway being returned to an earlier alignment, and certainly the longest era (34 years) between the changes.
A large sign reading "US 44 to I-86" on US 44 westbound in Ashford now reads "CT 74 to I-84". Steve Alpert has photos on his US 44 page.
As the years passed, the Buckland Five Corners intersection became a congestion and safety problem, and was redesigned. In October 1993, the Route 74 leg was closed off, and Route 74 was realigned. It now ends at Route 194 a short distance north of Route 30.
Between 1962 and 1993, Route 74 used to intersect Route 30 twice: once at Five Corners in South Windsor, and once again in Tolland. From South Windsor, Route 74 eastbound branched to the left from Route 30 northbound -- a compass-busting intersection that is rare in Connecticut and unknown in many states.
A couple decades back (and may still be the case), parts of Route 74 in South Windsor were signposted north and south.